Hippocampal theta sequences
Hippocampal theta sequences
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DOI：
10.1002/hipo.20345
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发表时间：
2007-01-01
期刊：
影响因子：
3.5
通讯作者：
Wilson, Matthew A.
中科院分区：
文献类型：
--
作者：
Foster, David J.;Wilson, Matthew A.
单个海马主神经元的活动在空间上是局部化的，因此只有当动物占据被称为细胞位场的环境区域时，每个神经元才是活跃的。此外，海马神经元的活动与海马EEG显示出一种特殊的时间关系，即当动物穿越位置场时，神经元发出的尖峰信号出现在EEG中共生的theta节律的逐渐早期阶段。这种关系被称为西塔进动。在观察到theta进动之后，一个长期存在的预测是，在同时记录的一组海马神经元中，神经元将按反映位置场行为顺序的序列进行放电。在这里，我们来检验这一预测。我们表明，清晰、有序的序列发生在theta期间，我们称之为theta序列，其中动物的空间经验的一部分以向前顺序呈现。我们进一步研究了theta序列与位相进动的关系，通过以这样一种方式洗牌峰相以保持峰相与位置之间的关系。这种抖动显著降低了theta序列的流行程度，同时保持theta相位进动不变，这表明theta相位进动的存在并不是theta序列的微不足道的预测。最后，我们讨论了theta序列与单个位置场之间的关系，以及theta序列在导航学习中可能的功能作用。(C)2007年Wiley-Liss，Inc.
The activity of individual hippocampal principal neurons is spatially localized such that each neuron is active only when the animal occupies an area of the environment known as the cell's place field. Additionally, the activity of hippocampal neurons exhibits a particular temporal relationship to the hippocampal EEG, such that spikes fired by the neuron occur at progressively earlier phases of the co-occurring theta rhythm in the EEG as the animal traverses the place field. This relationship is known as theta precession. A long-standing prediction following the observation of theta precession has been that among a collection of hippocampal neurons recorded simultaneously, the neurons will fire in sequences reflecting the behavioral order of the place fields. Here we examine this prediction. We show that clear, ordered sequences occur during theta, which we name theta sequences, in which a portion of the animal's spatial experience is played out in forwards order. We further investigate the relationship of theta sequences to phase precession by shuffling spike phases in such a way as to preserve the relationship between spike phase and position. This jitter significantly reduces the prevalence of theta sequences while leaving theta phase precession intact, suggesting that the presence of theta phase precession is not trivially predictive of theta sequences. Finally, we discuss the relationship between theta sequences and individual place fields, and the possible functional role of theta sequences in navigational learning. (C) 2007 Wiley-Liss, Inc.